Child/adolescent obesity is one of the most pressing public health problems today;it disproportionately affects Hispanic and Black children/adolescents as well as those living in poverty. Lack of physical activity and poor diet are well-documented contributors to child/adolescent obesity and reflect these same disparities. Environmental contexts may provide new answers to the origins of these disparities. Though recent studies have begun to elucidate the influence of neighborhoods on child/adolescent weight and weight related behaviors, schools remain an understudied environmental context. My long-range goal is to increase understanding of the impact of schools on the health of children/adolescents and their potential contribution to racial/ethnic and/or socioeconomic disparities. Coupled with this goal is my desire to build relationships between clinicians, researchers, and policy makers so that empirical findings can be translated into effective interventions. My career development plan proposes additional training and mentorship in three areas critical to my development as an independent researcher: (1) population health sciences, including the social determinants of health (social epidemiology), demographic theory and methods, sociology (urban sociology, neighborhood influences, and social stratification), and economics;(2) advanced methods needed to analyze contextual influences on health (multi-level analysis, multi-equation models, sociometric analysis), as well as methods to address causal inference;and (3) substantive understanding of the role of macro-social forces, such as educational opportunities, on health. My research plan includes 3 aims: (1) To determine the extent to which school factors contribute to racial/ethnic differences in individual dietary intake;(2) To determine the extent to which school factors contribute to racial/ethnic and/or socioeconomic differences in individual physical activity and weight trajectories from adolescence to adulthood;and (3) To simultaneously examine the influence of school context and two other potentially influential contexts-peer networks and neighborhood environments-on physical activity and weight gain trajectories. The career development plan will provide the training necessary to support an R01 application toward the end of this proposed award period and the research proposed will lay the ground work for identifying school-based interventions that can reverse the obesity epidemic and eliminate disparities.